Related Clues:
- Like neon and xenon
- Like neon and argon
- Opposite of active
- Like xenon and helium
- Perfectly still
- Like liquid nitrogen
- Unable to react, as helium
- Like 103-Down
- Chemically nonreactive
- Phlegmatic
- Couchbound, perhaps
- Utterly lethargic
- Chemically quiet
- Hard to get a reaction out of
- Unable to react chemically